Here goes, I dumped paper mario 2 into iso image. the iso works fine in dolhin as expected but I'm trying to dump all my library on bluray discs for storage and aim at compressing games as much as possible.
After dumping iso size is the usual 1.49Gb (you know the constant size for all gc discs). when I used dolphin built in compression I saved about 300mb. When I 7-zipped it I saved just about the same. What surprised me, was shrinking the iso with gcmutility as it saved me around 900mb!

my question is how could the difference be so big if all those utilities use similar algorithm to get rid of the gibirish data that fills the disc?
I have been doing readings about gcmutility and sometimes it mentions that game with audio streaming might have issues with shrinked isos. Is there a list of games that has those issues? I would much rather use gcmutility rather than dolhin due to the huge difference of saving space.

delroth
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Quote:my question is how could the difference be so big if all those utilities use similar algorithm to get rid of the gibirish data that fills the disc?

They don't use a similar algorithm. Both Dolphin's compression and 7z are completely lossless while I guess gcmutility shrinks the disc by removing "unused" sectors and moving things around the FST. Additionally Dolphin's compression allows arbitrary seeks while 7z does not provide that (which is why 7z will often give better results).

If you don't get any issues with games shrinked by gcmutility, go ahead with it, but you should probably test the games after shrinking (and please, do not report bugs to the Dolphin devs if you're using such tools to reduce your games size).

Quote:my question is how could the difference be so big if all those utilities use similar algorithm to get rid of the gibirish data that fills the disc?

They don't use a similar algorithm. Both Dolphin's compression and 7z are completely lossless while I guess gcmutility shrinks the disc by removing "unused" sectors and moving things around the FST. Additionally Dolphin's compression allows arbitrary seeks while 7z does not provide that (which is why 7z will often give better results).

If you don't get any issues with games shrinked by gcmutility, go ahead with it, but you should probably test the games after shrinking (and please, do not report bugs to the Dolphin devs if you're using such tools to reduce your games size).

thanks, it all make sense now. I tested few games so far after shrinking with gcmutility and they all play fine, although I would hate to find out later on that they break somewhere in the middle of the game. For sure, shrinking with gcmuti and then 7-zipping provides best results (14mb for animal crossing for example) but for now I will keep full iso dumps. If someone used extensively gcmuti please let me know of any games that have issues on dolphin, since after dumping all games my gamecube goes to the basement lol

(04-02-2012, 02:11 PM)shuffle2 Wrote: If you are using gcmutility* it would probably be better for you to just enable NTFS compression on your gamecube iso directory instead of using 7zip.

*however I would always recommend using dolphin's compression instead of any external tool.

Like I said, I will be storing games on bluray discs, and dont believe it would work on optical media. I would prefer to use dolphin too, but the difference is quite striking to ignore. dolphin scrubbs wii isos, why not gamecube?

oh I missed the bluray part.
dolphin scrubs wii isos because it *has* to. Otherwise there would be little to no compression at all (because the entire image is encrypted).

There are many ways to decrease file sizes, all relating to being able to have special cases, such as:
decrypting wii images along with scrubbing
decompressing common file types on the gc/wii images in order to let our compressor do it better and transparently recompressing it into the game's format when read.
other things such as removing "unneeded" partitions on wii images.
give up on streaming formats and force the decompressor to load the entire image in ram.

All of these options have significant run-time performance and/or data "safety" issues.

This comes down to us storing as much of the original content as possible, in a manner fit for streaming decompression.

Since ALL the gamecube games produced can fit comfortably on a single modern hard drive, the minimal space savings offered by possibly loosing important data forever is just not worth it.

(04-02-2012, 08:27 PM)shuffle2 Wrote: oh I missed the bluray part.
dolphin scrubs wii isos because it *has* to. Otherwise there would be little to no compression at all (because the entire image is encrypted).

Isn't it the same case with GameCube? from my testing it would appear so. using dolphin compression all but very few games remain at above 1GB. Whether we like it or not, a bigger portion of dolphin users is not using their own dumps, and rather uses scene releases that I recently checked are all shrinked. if I asked how big in size is the image of animal crossing after compressed, would people say 1.447GB or 25-30MB? Dolphin and 7zip saves only a few megs on compression on this game because it's the same story as with wii - the filler of the disc is filled with random junk that barely compress.

in any case, yeah I think I will stick with full iso images for the peace of mind.